2. amps-preamps
  3. 153960-1009

Smoke on my power amp

I was listening the music with the right speaker wire detached to listen to the left speaker alone. The speaker wire was still attached at the amp side. My preamp does not have the balance knob.
After 20 secs or so, there was a smoke on my power amp.
I quickly turn off the amp.
Once smoke comes, would it be safe to turn it on again? I wonder whether it is permanently damaged.
Is it not safe to listen to the music with the speaker wire detached from one speaker but still attached on the amp side?
My amp is Plinius SA 102.
Any comment?
thx


128x128ihcho
almarg's avatar
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almarg
9,670 posts
 
@itsjustme, thanks for your comment. I would add, though, that in the specific case of tube amps having output transformers it seems pretty well established that such amps should not be operated unloaded while they are processing a signal. The concern being that "inductive kick" occurring in the transformer in that situation may damage the transformer and/or the output tubes. And I suppose the same may apply to the many McIntosh solid state amplifiers which have autoformers at their outputs.

Regards,
-- Al

imhififan's avatar
imhififan
2,176 posts
 
I also like to point out that without a Zobel-network and output inductor built-in, some direct-coupled output solid state amplifier can becomes unstable and go into oscillation without connected to a load, especially connected to a pair of long speaker cable with open end!
 
This is an example of amplifier schematic featured Zobel and inductor: 

https://www.seventransistorlabs.com/tmoranwms/Circuits_2008/2N6254_Power_Amp.gif
wrenth
26 posts
 
In case of TubeAmps!!! Never allow to run it without speakers connected!!!!
In case of the rest, do not shortcut the speaker cable.
Good amps should have safety measures but lets be honest... most up to 5000$ do not have it.
In case of smoke NEVER POWER SUCH EQUIPMENT unless you are professional. Give it back to pro service.
After all YOU HAVE ONE LIFE and this is electrical device.
This is one of the reason why i finally ended with MCintosh.
Not all savings are savings in time function.
Thx,
audiobill1
51 posts
 
Were you smokin' before the amp was smoking?
ihcho's avatar
ihcho OP
612 posts
 
Thanks for all your replies.
The fuses look OK.
I'm thinking of selling it as it is, or getting it fixed.
This amp is so heavy, and shipping is a nightmare.

In the meanwhile, I have a spare AR amp and a Nakamichi Stasis amp, and will listen to them, and just enjoy music, no more playing around with cables.


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